Legionellosis Outbreak Associated
with a Hotel Fountain, Chicago 2012
June 11, 2013
Shamika Smith, MPH
Epidemiologist
City of Chicago
Mayor Rahm Emanuel
Chicago Department of Public Health
Commissioner Bechara Choucair, M.D.
Legionellosis
• Bacteria ubiquitous in environment, typically
water
• Transmitted through aerosolization or
aspiration of Legionella-contaminated water
• Immunocompromised individuals are most
susceptible
Difference between
LD and PF
Legionnaires' disease
(LD)
Clinical features
Pneumonia, cough, fever
Pontiac Fever
(PF)
Radiographic pneumonia Yes
Flu-like illness (fever, chills,
malaise) without
pneumonia
No
Incubation period
2-14 days after exposure
24-72 hours after exposure
Etiologic agent
Legionella species
Legionella species
Attack rate
< 5%
> 90%
Isolation of organism
Possible
Never
Outcome
Hospitalization common
Case-fatality rate: 5-30%
Hospitalization uncommon
Case-fatality rate: 0%
CDC. Top 10 Things Every Clinician Needs to Know About Legionellosis. 2013. Retrieved from http://www.cdc.gov/legionella/clinicians.html
Reported Legionellosis Case Counts, 1990-2011*
3000
United States (CDC)
2000
1000
0
160
Illinois (IDPH)
120
80
40
0
50
40
Chicago (CDPH)
30
20
10
0
90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11
*Counts for U.S. (2011) not yet published.
Reported Legionellosis cases
by month of onset,
Chicago, 2001 - 2010
September 2006
N=12
Reported
residences
of cluster
casepatients
August 2007
N=14
June-Aug. 2010
N=18
Outbreak Identification
• Aug. 14, 2012: Company A contacted CDPH reporting:
--30 cases of respiratory illness
--several cases of pneumonia; 1 death
• CDPH contacted Hotel X-learned that guest (not Company
A) also reported illness
• Conference held at Hotel X from Jul. 30- Aug. 3
-- Approximately 600 attendees
-- Event I (7/30-8/1): 427 people
-- Event II (8/2-8/3): 266 people
-- 80 people attended both event
July and August Events
Sunday
Monday
Tuesday
Wed
Thursday
Friday
Saturday
JULY 15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
AUG 1
2
3
4
5
6
7
8
9
10
11
12
13
14 CDPH
notified
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
July and August Events
Sunday
Monday
Tuesday
Wed
Thursday
Friday
Saturday
JULY 15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
AUG 1
2
3
4
5
6
7
8
9
10
11
12
13
14 Water
Closures
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
July and August Events
Sunday
Monday
Tuesday
Wed
Thursday
Friday
Saturday
JULY 15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
AUG 1
2
3
4
5
6
7
8
9
10
11
12
13
14 Water
Closures
15 Water
Drained
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Case Finding
• Hotel reached out to guests 7/16-8/15
--Earliest exposure date: 7/26- 10 days= 7/16
--The day fountain, pool, spa drained: 8/15
• CDPH contacted other hotel event organizers
• Hotel unable to obtain mailing addresses for ~40% of
guests by 8/20
• Three press releases; media interviews
Methods: Survey Development
• Exploratory interviews with Company A employees
• Etiology unknown, therefore reviewed
– Legionella questionnaire
– CDC’s acute respiratory illness questionnaire
• Piloted draft questionnaire, 8/15 (morning)
• Questionnaire sent to all Company A hotel guests via
Health Alert Network (HAN), 8/15 (afternoon)
July and August Events
Sunday
Monday
Tuesday
Wed
Thursday
Friday
Saturday
JULY 15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
AUG 1
2
3
4
5
6
7
8
9
10
11
12
13
14 CDPH
notified
15 Survey
EPI-X
16
17
18
25
Sample 1
19
20
21
22
23
24
26
27
28
29
30
31
Methods:
Environmental Health
• Illinois Department of Public Health (IDPH),
Environmental Health inspected/sampled:
– Whirlpool spa
– Indoor pool
– Fountain in lobby
– Locker rooms
– Steam room
– Sauna
– Guest shower heads
• CDC consulted
July and August Events
Sunday
Monday
Tuesday
Wed
Thursday
Friday
Saturday
JULY 15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
AUG 1
2
3
4
5
6
7
8
9
10
11
12
13
14 CDPH
notified
15 Survey
EPI-X
16
17 Data
analysis
18
Sample 2
Sample 3
25
Sample 1
19
20
21
22
23
24
26
27
28
29
30
31
Preliminary Data Analysis
• Fountain exposure significantly associated with
illness
• Case definition: hospitalized, pneumonia dx, chest
x-ray ordered
Fountain Exposure
Yes
No
Yes
13
7
20
No
51
99
150
64
106
170
Case
P-value=.0074
7-Sep
6-Sep
5-Sep
70
4-Sep
80
3-Sep
2-Sep
1-Sep
31-Aug
30-Aug
29-Aug
28-Aug
27-Aug
26-Aug
25-Aug
24-Aug
23-Aug
22-Aug
21-Aug
Number of calls received
(N=250)
Dates of press releases
60
50
40
30
20
10
0
HAN Survey Results and
Data from CDPH Phone Bank
HAN Survey from Company A
• 328 responses, ~ 1/3 reporting illness
• 1 confirmed case (1 expired)
Phone Bank
• 145 surveys completed, most reporting illness
• 10 confirmed cases (2 expired)
Confirmed Legionnaires’
Disease (LD)
Case definition: A person who stayed at or visited the
hotel with illness onset within 2-14 days of exposure to
the hotel, AND with radiographically- or autopsyconfirmed pneumonia AND with laboratory evidence of
Legionella infection.
Confirmed LD Laboratory
Criteria
• Isolation, through culture, of any Legionella
organism from resp. secretions, lung tissue, pleural
fluid, or other normally sterile site
• Detection of Legionella pneumophila serogroup 1
(Lp1) antigen in urine
• Seroconversion (4-fold increase in antibody titer to
Lp1 between acute and convalescent titers)
• Detection by Lp1 molecular testing (e.g., PCR)
Suspect Legionnaires’ Disease
Case definition: A person who stayed at or visited
the hotel with illness onset within 2-14 days of
exposure to the hotel, who had radiographically- confirmed pneumonia, or clinical diagnosis of
pneumonia, but without laboratory confirmation of
Legionella infection.
Pontiac Fever
Case definition: Fever, either subjective or
documented, in a person who stayed at or visited the
hotel with illness onset within 3 days of exposure to
hotel, AND at least one of the following: cough,
headache, SOB, myalgias, diarrhea, or vomiting,
and who does not meet definition for confirmed or
suspect LD.
Respiratory
Illness
by
Date
of
Symptom
Onset
25
(N=114) Legionnaires disease confirmed
Legionnaires disease suspect
Pontiac Fever
Case fatality
Number of Cases
20
15
10
CDPH notified
Fountain, pool and
spa drained
5
0
21
23
25
27
July
29
31
2
4
6
8
10
12
August
14
16
18
20
22
Case-patient
Characteristics
All cases (N=114)
Confirmed LD (N=11)
64
91
47 yrs (22-82 yrs)
65.5 yrs (49-82 yrs)
% Hospitalized
13
82
Deaths
0
3
N/A
Obesity (1), HIV (1), COPD
(1), HTN/CVD (5),
current/former smokers
(2/2)
% Male
Median age
(range)
Underlying illness/
risk
Case-patients’ Symptoms
All cases
Symptoms
Confirmed LD
(n/N)
%
(n/N)
%
Fever
113/114
99
10/11
91
Cough
76/110
69
9/10
90
Shortness of
Breath
65/107
61
8/10
80
Vomiting or
Diarrhea
57/105
54
5/11
45
Exposure Assessment (106 ills, 194 wells)
Exposure
# Exposed
RR(CI)
p
Lobby Fountain
123
2.13 (1.64, 2.77)
<0.0001
Lobby Bar
211
1.25 (1.09, 1.44)
0.003
Whirlpool Spa
5
2.38 (0.40, 13.99)
0.378
Pool
4
4.76 (0.50, 45.10)
0.302
Sauna
3
0.79 (0.07, 8.63)
1.000
Steam Room
4
1.59 (0.23, 11.08)
0.322
Guest Shower
236
1.00 (0.92, 1.07)
0.899
Guest Bath
50
0.89 (0.53, 1.50)
0.666
Environmental Results
• Positive: Lobby fountain, locker rooms (men and
women shower heads and sinks), swimming pool,
whirlpool
• Negative: Guest room shower heads
Matching Isolates
• Lp1 environmental isolates and a clinical isolate
from a confirmed LD case-patient had matching
sequence-based types.
Contributing Factors to
Legionella Growth in Fountain
• Lack of written cleaning and maintenance
program
• Presence of submerged lighting
• Presence of dirt, organic matter, or other debris
in the water basin
After
Before
Remediation
• Fountain removed
• Installation of chlorine dioxide treatment system
to water supply
– Must keep monthly operational records
– IDPH inspection every 2 years
Conclusions
• Point source outbreak
• Environmental testing identified Legionella in the
hotel’s potable water system.
• Poor fountain maintenance likely created favorable
conditions for Legionella overgrowth
• Epidemiologic and molecular typing data confirmed
that fountain was likely the source
Acknowledgements
• Centers for Disease Control and Prevention
– National Center for Immunization and
Respiratory Diseases, Division of Bacterial
Diseases
• Illinois Department of Public Health
– Craig Conover, MD, MPH
– Connie Austin, DVM, PhD
– Division of Environmental Health
– Division of Infectious Diseases
Acknowledgements
• AL, AR, AZ, CA, CO, FL, GA, IA, IN, KS, MA, MD,
ME, MI, MN, MO, NC, NE, NJ, NY, OH, OR, PA, TN,
TX, VA, WI, WV, Ireland, Canada
• Chicago Department of Public Health
– Communicable Disease Program
– Emergency Preparedness Program
@ChiPublicHealth
facebook.com/ChicagoPublicHealth
312.747.9884
[email protected]
www.CityofChicago.org/Health
Public health Messaging
• IDPH Environmental laboratory results
• Exposures eliminated
– Fountain removed
– Pool, spa, locker rooms inaccessible to public
• Updating case counts
Legionellosis cases by month
of onset, 2011-2012
20
Number of cases
15
10
5
0
JAN FEB MAR APR MAY JUN
JUL AUG SEP OCT NOV DEC
SU
July
22
29
M
16
23
30
TU
17
24
31
W
18
25
1
TH
19
26
2
F
20
27
3
SA
21
28
4
9
16
23
10
17
24
11
18
25
A u g u st
5
12
19
6
13
20
7
14
21
8
15
22
SU
July
22
29
M
16
23
30
TU
17
24
31
W
18
25
1
TH
19
26
2
F
20
27
3
SA
21
28
4
9
16
23
10
17
24
11
18
25
A u g u st
5
12
19
6
13
20
7
14
21
8
15
22
Reported 10-year incidence rates per
100,000 adult residents, by Chicago
community area, 2001-August 2010
Reported cases per
100,000 adults
Approximate reported residence of
Chicago case-patients, with spatial
clustering denoted in gray
Case-patients’ Characteristics
All Cases (N=114)
Confirmed LD (N=11)
64
91
47 (22-82 yrs)
65.5 (49-82 yrs)
% Hospitalized
13
82
Deaths
0
3
N/A
Obesity(1), HIV(1),
COPD(1), HTN/CVD(5),
current/former smokers
(2/2)
% Male
Median age (range)
Underlying Illness/risk
Timeline
Bakery re-opening
Inspection and
product recall
Bakery closure
29
July
= outbreak
30 3
1
August
12
18 22 23
30
Why the Increase?
• Increasing population of older persons
• Increasing population of persons at high risk
for infection
• Improved diagnosis and reporting
• Weather conditions..
July and August Events
Sunday
Monday
Tuesday
Wed
Thursday
Friday
Saturday
JULY 15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
AUG 1
2
3
4
5
6
7
8
9
10
11
12
13
14 CDPH
notified
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
July and August Events
Sunday
Monday
Tuesday
Wed
Thursday
Friday
Saturday
July
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
2
3
4
5
6
7
8
9
10
11
12
13
14 CDPH
notified
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
1
August
July and August Events
SU
Jul y
22
29
M
16
23
30
TU
17
24
31
W
18
25
1
TH
19
26
2
F
20
27
3
SA
21
28
4
9
16
23
10
17
24
11
18
25
A u g u st
5
12
19
6
13
20
7
14
21
8
15
22
July and August Events
SU
Jul y
22
29
M
16
23
30
TU
17
24
31
W
18
25
1
TH
19
26
2
F
20
27
3
SA
21
28
4
9
16
23
10
17
24
11
18
25
A u g u st
5
12
19
6
13
20
7
14
21
8
15
22
July and August Events
SU
Jul y
22
29
M
16
23
30
TU
17
24
31
W
18
25
1
TH
19
26
2
F
20
27
3
SA
21
28
4
9
16
23
10
17
24
11
18
25
A u g u st
5
12
19
6
13
20
7
14
21
8
15
22
July and August Events
SU
Jul y
22
29
M
16
23
30
TU
17
24
31
W
18
25
1
TH
19
26
2
F
20
27
3
SA
21
28
4
9
16
23
10
17
24
11
18
25
A u g u st
5
12
19
6
13
20
7
14
21
8
15
22